May 22, 2009

Birds Of Harsh Climates Sing The Blues

Researchers have discovered answers to the long pondered question: Why is it that some birds sing such sophisticated songs and others sing so simply?

The findings, which credit climate patterns as the primary cause, were revealed in an online publication of Current Biology on May 21st, a Cell Press publication, a public release accounted.

The ranges in song patterns of various species of mockingbird, researchers inform, vary with climate in the many diverse places they inhabit. Particularly, species of more irregular and erratic climates have a propensity to have more remarkable singing abilities.

"Local climatic patterns are great indicators of how demanding life can be at a certain site," said Carlos Botero of the National Evolutionary Synthesis Center. "For example, harsher winters, drier dry seasons, or highly unpredictable weather patterns make it harder for animals to survive and reproduce. Our data show that mockingbirds living in more demanding environments tend to have more elaborate song displays. We think that this surprising relationship reflects the fact that just as climatic patterns tell a lot about a site, singing behavior also tells a lot about a singer."

He explained that male songbirds attract their mates by singing, and by singing they also ward off their rivals, indicating that their songs tell quite a bit about their superiority and state of being. So, whether the songs they sing are creative or imitative, males must learn the various song elements. By listening to the variances of quality in those songs, something distinguishable can be understood about the individual male's brain power.

In an unpredictable climate, the males' song becomes very critical as females are more selective when choosing a mate, Botero added. The reproductive consequences of picking an unsuitable partner can be serious when times are difficult. When that happens, song demonstrations are likely to become progressively more complex as males strive harder to draw a mate. A comparable argument could be made for signals used in the context of male-male competition, Botero said.

Additionally, a male that sings elaborate songs typically is in great health, as males that sing more complex songs also "tend to carry fewer parasites, and have offspring that are more likely to survive," Botero said.

Human-kind may even identify with these findings in mockingbirds, Botero said.

Human manifestations such as language, the arts and music, might have developed as signals of intelligence through sexual selection processes, he said.

"Our data suggest that a similar process might be going on in the songbirds, and this possibility presents us with a unique opportunity to understand the forces behind the evolution of traits that are so important for our own species."